feat(dogfood): kebab reset --orphans-only — purge stored docs outside walker scope

PR #148 auto-purges only filesystem-missing files (conservative — leaves
on-disk-but-out-of-scope docs alone for data safety). This is the explicit
complement: when the user has narrowed include / widened exclude / removed
a sub-directory from the workspace and WANTS the stored docs reconciled,
they invoke 'kebab reset --orphans-only'.

Confirm prompt with orphan count + sample paths; --yes required in
non-TTY. SQLite purge via existing purge_deleted_workspace_path (PR #148)
+ vector store delete_by_chunk_ids when configured. No fs existence
check — orphans-only is the explicit 'I know what I'm doing' variant.

dogfood follow-up to PR #148 (file deletion auto-purge).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-cli/src/wire.rs

@@ -365,6 +365,8 @@ mod tests {
             scope: kebab_app::ResetScope::DataOnly,
             removed_paths: vec![std::path::PathBuf::from("/tmp/x")],
             embedding_rows_truncated: 0,
+            orphans_purged: 0,
+            purged_paths: vec![],
         };
         let v = wire_reset(&r);
         assert_eq!(schema_of(&v), Some("reset_report.v1"));